Studying changes in breast composition is imperative to increase our understanding of breast carcinoma. Detection of metabolic changes between breast tumours and normal tissue using Magnetic Resonance Spectrosopy (MRS) have previously shown different water/fat ratios together with elevated choline containing compounds in breast tumour compared to normals. This difference may suggest choline as a spectral marker for breast cancer. However such possible variations in metabolites may exist within normals throughout the duration of the menstrual cycle. This is what we are currently assessing at 4 Tesla which provides better spectral resolution than 1.5 Tesla. To date five normal subjects have been tested over the course of their menstrual cycle. Each subject is tested twice a week for four weeks. Two images are acquired, axial and sagittal, and spectroscopy data acquired from a voxel position taken from the sagittal image. Recently, B1 maps are being acquired together with phantom spectroscopy in order to quantify the data. The spectroscopy data is being analysed using SAGE IDL. At this time, data analysis has shown that elevated choline levels are not present in normal breast parenchyma throughout the course of a menstrual cycle. Further investigation will include analysis of fat and lipid content, as recent data suggests variability throughout the course of the cycle.